The riddle in the key level might give you a hint at the solution! If you're still stuck, try interacting with other things in the room :D
Thanks for playing!
Is this is available for purchase on Steam? There's a problem with my zip code on my debit card since I've moved, but Steam still lets me purchase games. I'd love to buy this compilation, being a huge fan of all these games. (Ultra Business Tycoon III as my very favourite), I know it's been greenlit!